<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
	<title>YUI Library Examples: Browser History Manager: Simple Navigation Bar</title>
    

    <meta http-equiv="content-type" content="text/html; charset=utf-8">
    	<link rel="stylesheet" type="text/css" href="../../assets/yui.css" >

<style>
/*Supplemental CSS for the YUI distribution*/
#custom-doc { width: 95%; min-width: 950px; }
#pagetitle {background-image: url(../../assets/bg_hd.gif);}
</style>

<link rel="stylesheet" type="text/css" href="../../assets/dpSyntaxHighlighter.css">
<!--Script and CSS includes for YUI dependencies on this page-->
<link rel="stylesheet" type="text/css" href="../../build/button/assets/skins/sam/button.css" />
<script type="text/javascript" src="../../build/yuiloader/yuiloader-min.js"></script>
<script type="text/javascript" src="../../build/dom/dom-min.js"></script>
<script type="text/javascript" src="../../build/event/event-min.js"></script>
<script type="text/javascript" src="../../build/connection/connection-min.js"></script>
<script type="text/javascript" src="../../build/history/history-min.js"></script>
<script type="text/javascript" src="../../build/element/element-min.js"></script>
<script type="text/javascript" src="../../build/button/button-min.js"></script>

<!--there is no custom header content for this example-->


<script type="text/javascript">
//enable passthrough of errors from YUI Event:
if ((typeof YAHOO !== "undefined") && (YAHOO.util) && (YAHOO.util.Event)) {
	YAHOO.util.Event.throwErrors = true;
}
</script>
</head>
<body id="yahoo-com" class="yui-skin-sam">
<div id="custom-doc" class="yui-t2">
<div id="hd">
	<div id="ygunav">
		<p><em><a href="http://developer.yahoo.com/yui/">YUI Library Home</a></em></p>
		<form action="http://search.yahoo.com/search" id="sitesearchform">
		<input name="vs" type="hidden" value="developer.yahoo.com">
		<input name="vs" type="hidden" value="yuiblog.com">
		<div id="sitesearch">
			<label for="searchinput">Site Search (YDN &amp; YUIBlog): </label>
			<input type="text" id="searchinput" name="p">
			<input type="submit" value="Search" id="searchsubmit" class="ygbt">
		</div>
		</form>	</div>
	<div id="ygma"><a href="../../"><img src="../../assets/yui.gif"  border="0" height="38"></a></div>
	<div id="pagetitle"><h1>YUI Library Examples: Browser History Manager: Simple Navigation Bar</h1></div>
</div>
<div id="bd">
	
	<div id="yui-main">
		<div class="yui-b">
		  <div class="yui-ge">
			  <div class="yui-u first example">

    
	<div class="promo">
	<h1>Browser History Manager: Simple Navigation Bar</h1>
	
	<div class="exampleIntro">
	<p>This example demonstrates how to use the Browser History Manager to "ajaxify" a simple navigation bar.</p>			
	</div>	
					
	<div class="example-container module  newWindow">
			<div id="example-canvas" class="bd">
	
		<p class="newWindowButton yui-skin-sam"><span id="newWindowLink"><span class="first-child"><a href="history-navbar_source.html" target="_blank">View example in new window.</a></span></span>		
	
		
		</div>
		
	
	</div>			
	</div>
		
	<h2 class="first">Basic markup</h2>

<textarea name="code" class="HTML" cols="60" rows="1">
<html>
  <head>
    <title>YUI Browser History Manager - Simple Navigation Bar Example</title>
  </head>
  <body>
    <div id="doc">
      <div id="hd">
        <h3>Navigation Links</h3>
        <div id="nav">
          <ul>
            <li><a href="?section=home">Home</a></li>
            <li><a href="?section=overview">Overview</a></li>
            <li><a href="?section=products">Products</a></li>
            <li><a href="?section=contactus">Contact Us</a></li>
          </ul>
        </div>
      </div>
      <div id="bd">
&lt;?php

$section = "home";
$sections = array("home", "overview", "products", "contactus");
if (isset($_GET["section"]) && in_array($_GET["section"], $sections)) {
    $section = $_GET["section"];
}

include( $section . ".php" );

?&gt;
      </div>
      <div id="ft">YUI Browser History Manager - Simple Navigation Bar Example</div>
    </div>
  </body>
</html>
</textarea>

<p>
  The small portion of PHP code is responsible for including the content specified by the "section" parameter in the URL.
  This technique avoids having to rewrite common parts of a web site such as header and footer.
</p>

<p>
  This page is already fully functional. However, clicking on the links in the navigation bar will refresh the entire
  page, including portions that are common to all the sections. This is highly inefficient (especially for a large web
  site), and using AJAX will allow us to optimize this. The idea is to use client-side scripting to intercept the click
  event, cancel it, and use the YUI Connection Manager to asynchronously load the content of the section, which we can
  then write to the document using innerHTML. The only downside of this approach is that it breaks the back/forward
  buttons, and individual sections cannot be bookmarked anymore. The Browser History Manager will help us work around
  this issue.
</p>

<h2>Add the markup required by the Browser History Manager</h2>

<textarea name="code" class="HTML" cols="60" rows="1">
<iframe id="yui-history-iframe" src="assets/blank.html"></iframe>
<input id="yui-history-field" type="hidden">
</textarea>

<p>
  This markup should be inserted right after the opening <code>body</code> tag.
</p>

<h2>Import the source files and dependencies</h2>

<p>
  In our example, we need the Connection Manager, Event Utility, DOM Utility, and the Browser History Manager:
</p>

<textarea name="code" class="HTML" cols="60" rows="1">
<script src="yahoo-dom-event.js"></script>
<script src="connection.js"></script>
<script src="history.js"></script>
</textarea>

<h2>Write the code necessary to load a section of the web site</h2>

<p>
  Use the YUI Connection Manager's <code>asyncRequest</code> to achieve this:
</p>

<textarea name="code" class="JScript" cols="60" rows="1">
function loadSection(section) {
    var url = section + ".php";

    function successHandler(obj) {
        // Use the response...
        YAHOO.util.Dom.get("bd").innerHTML = obj.responseText;
    }

    function failureHandler(obj) {
        // Fallback...
        location.href = "?section=" + section;
    }

    YAHOO.util.Connect.asyncRequest("GET", url,
        {
            success:successHandler,
            failure:failureHandler
        }
    );
}
</textarea>

<h2>Design your application</h2>

<p>
  In our simple example, we have only one module, represented by the navigation bar. We will refer to this module using
  the identifier "navbar". The state of the navigation module will be represented using the name of the corresponding
  section ("home", "overview", "products", etc.)
</p>

<h2>Retrieve the initial state of the navigation module</h2>

<p>
  Use the <code>YAHOO.util.History.getBookmarkedState</code> method to find out the initial state of a module according
  to the URL fragment identifier (which is present if the user had previously bookmarked the application). In our
  example, we also use the <code>YAHOO.util.History.getQueryStringParameter</code> method to find out the initial state
  of a module according to the query string (which is present if the user reached the page using a search engine, or if
  the user did not have scripting enabled when previously bookmarking the page). Finally, default to "home":
</p>

<textarea name="code" class="JScript" cols="60" rows="1">
var bookmarkedSection = YAHOO.util.History.getBookmarkedState("navbar");
var querySection = YAHOO.util.History.getQueryStringParameter("section");
var initialSection = bookmarkedSection || querySection || "home";
</textarea>

<h2>Register the navigation module</h2>

<p>
  Use the <code>YAHOO.util.History.register</code> method, passing in the navigation module identifier, the initial
  state of the navigation module, and the callback function that will be called when the state of the navigation
  module has changed:
</p>

<textarea name="code" class="JScript" cols="60" rows="1">
YAHOO.util.History.register("navbar", initialSection, function (state) {
    // Load the appropriate section:
    loadSection(state);
});
</textarea>

<h2>Write the code that initializes your application</h2>

<p>
  First of all, we want to change the behavior of the links in the navigation bar. In order to do this, we simply
  enumerate them, and attach to each individual anchor an <code>onclick</code> handler. In the <code>onclick</code>
  handler, we cancel the event's default behavior and do some custom action.
</p>

<p>
  We also need to display the default section if a section was requested via the URL fragment identifier, and that
  section is different from the one loaded using PHP:
</p>

<textarea name="code" class="JScript" cols="60" rows="1">
function initializeNavigationBar() {
    // Process links
    var anchors, i, len, anchor, href, section, currentSection;
    anchors = YAHOO.util.Dom.get("nav").getElementsByTagName("a");
    for (i = 0, len = anchors.length; i < len; i++) {
        anchor = anchors[i];
        YAHOO.util.Event.addListener(anchor, "click", function (evt) {
            href = this.getAttribute("href");
            section = YAHOO.util.History.getQueryStringParameter("section", href) || "home";
            // If the Browser History Manager was not successfuly initialized,
            // the following call to YAHOO.util.History.navigate will throw an
            // exception. We need to catch it and update the UI. The only
            // problem is that this new state will not be added to the browser
            // history.
            //
            // Another solution is to make sure this is an A-grade browser.
            // In that case, under normal circumstances, no exception should
            // be thrown here.
            try {
                YAHOO.util.History.navigate("navbar", section);
            } catch (e) {
                loadSection(section);
            }
            YAHOO.util.Event.preventDefault(evt);
        });
    }

    // This is the tricky part... The window's onload handler is called when the
    // user comes back to your page using the back button. In this case, the
    // actual section that needs to be loaded corresponds to the last section
    // visited before leaving the page, and not the initial section. This can
    // be retrieved using getCurrentState:
    currentSection = YAHOO.util.History.getCurrentState("navbar");
    loadSection(currentSection);
}
</textarea>

<h2>Use to the Browser History Manager <code>onReady</code> method</h2>

<p>
  Use the Browser History Manager <code>onReady</code> method to initialize the application.
</p>

<textarea name="code" class="JScript" cols="60" rows="1">
YAHOO.util.History.onReady(function () {
    initializeNavigationBar();
});
</textarea>

<h2>Initialize the Browser History Manager</h2>

<p>
  Simply call <code>YAHOO.util.History.initialize</code>, passing in the id of the input field and IFrame we inserted
  in our static markup:
</p>

<textarea name="code" class="JScript" cols="60" rows="1">
// Initialize the browser history management library.
try {
    YAHOO.util.History.initialize("yui-history-field", "yui-history-iframe");
} catch (e) {
    // The only exception that gets thrown here is when the browser is
    // not supported (Opera, or not A-grade) Degrade gracefully.
    // Note that we have two options here to degrade gracefully:
    //   1) Call initializeNavigationBar. The page will use Ajax/DHTML,
    //      but the back/forward buttons will not work.
    //   2) Initialize our module. The page will not use Ajax/DHTML,
    //      but the back/forward buttons will work. This is what we
    //      chose to do here:
    loadSection(initSection);
}
</textarea>
<h2>Configuration for This Example</h2>

<p>You can load the necessary JavaScript and CSS for this example from Yahoo's servers.  <a href="http://developer.yahoo.com/yui/articles/hosting/?yahoo&dom&event&connection&history&MIN#configure">Click here to load the YUI Dependency Configurator with all of this example's dependencies preconfigured</a>.</p>

				</div>
				<div class="yui-u">
					
				
					<div id="examples">
						<h3 class='firstContent'>Browser History Manager Examples:</h3>
	
						<div id="exampleToc">
							<ul>
								<li class='selected'><a href='../history/history-navbar.html'>Simple Navigation Bar</a></li><li><a href='../history/history-tabview.html'>TabView Control</a></li><li><a href='../history/history-calendar.html'>Calendar Control</a></li><li><a href='../history/history-multiple.html'>Multiple Modules</a></li><li><a href='../datatable/dt_bhm.html'>Integrating Browser History Manager with Server-side Pagination and Sorting (included with examples for DataTable Control)</a></li>							</ul>
						</div>
					</div>
					
					<div id="module">
						<h3>More Browser History Manager Resources:</h3>
						<ul>
							<li><a href="http://developer.yahoo.com/yui/history/">User's Guide</a> (external)</li>
						<li><a href="../../docs/module_history.html">API Documentation</a></li>
                            
                            
							<li><a href="http://yuiblog.com/assets/pdf/cheatsheets/history.pdf">Cheat Sheet PDF</a> (external)</li></ul>
					</div>
			  </div>
		</div>
		
		</div>
	</div>


<div class="yui-b" id="tocWrapper">
<!-- TABLE OF CONTENTS -->
<div id="toc">
	
<ul>
<li class="sect first">Yahoo! UI Library</li><li class="item"><a title="The Yahoo! User Interface Library (YUI)" href="http://developer.yahoo.com/yui/">Home (external)</a></li><li class="item"><a title="The Yahoo! User Interface Blog" href="http://yuiblog.com">YUIBlog (external)</a></li><li class="item"><a title="YUILibrary.com hosts the YUI community forums" href="http://yuilibrary.com/forum/">YUI Discussion Forum (external)</a></li><li class="item"><a title="The YUI Library source can be checked out from GitHub" href="http://github.com/yui/">YUI on GitHub</a></li><li class="item"><a title="Instantly searchable API documentation for the entire YUI library." href="../../docs/index.html">API Documentation</a></li><li class="item"><a title="Examples of every YUI utility and control in action" href="../../examples/">Functional Examples</a></li><li class="item"><a title="Videos and podcasts from the YUI Team and from the Yahoo! frontend engineering community." href="http://developer.yahoo.com/yui/theater/">YUI Theater (external)</a></li><li class="item"><a title="YUI is free and open, offered under a BSD license." href="http://developer.yahoo.com/yui/license.html">YUI License (external)</a></li><li class="sect">YUI Functional Examples</li><li class="item"><a title="The YUI Animation Utility - Functional Examples" href="../../examples/animation/index.html">Animation</a></li><li class="item"><a title="The YUI AutoComplete Control - Functional Examples" href="../../examples/autocomplete/index.html">AutoComplete</a></li><li class="selected "><a title="The YUI Browser History Manager - Functional Examples" href="../../examples/history/index.html">Browser History Manager</a></li><li class="item"><a title="The YUI Button Control - Functional Examples" href="../../examples/button/index.html">Button</a></li><li class="item"><a title="The YUI Calendar Control - Functional Examples" href="../../examples/calendar/index.html">Calendar</a></li><li class="item"><a title="The YUI Carousel Control - Functional Examples" href="../../examples/carousel/index.html">Carousel</a></li><li class="item"><a title="The YUI Charts Control - Functional Examples" href="../../examples/charts/index.html">Charts</a></li><li class="item"><a title="The YUI Color Picker Control - Functional Examples" href="../../examples/colorpicker/index.html">Color Picker</a></li><li class="item"><a title="The YUI Cookie Utility - Functional Examples" href="../../examples/cookie/index.html">Cookie</a></li><li class="item"><a title="The YUI Connection Manager (AJAX) - Functional Examples" href="../../examples/connection/index.html">Connection Manager</a></li><li class="item"><a title="The YUI Container Family (Module, Overlay, Tooltip, Panel, Dialog, SimpleDialog) - Functional Examples" href="../../examples/container/index.html">Container</a></li><li class="item"><a title="The YUI DataTable Control - Functional Examples" href="../../examples/datatable/index.html">DataTable</a></li><li class="item"><a title="The YUI Dom Collection - Functional Examples" href="../../examples/dom/index.html">Dom</a></li><li class="item"><a title="The YUI Drag &amp; Drop Utility - Functional Examples" href="../../examples/dragdrop/index.html">Drag &amp; Drop</a></li><li class="item"><a title="The YUI Event Utility - Functional Examples" href="../../examples/event/index.html">Event</a></li><li class="item"><a title="The YUI Get Utility - Functional Examples" href="../../examples/get/index.html">Get</a></li><li class="item"><a title="The YUI ImageCropper Control - Functional Examples" href="../../examples/imagecropper/index.html">ImageCropper</a></li><li class="item"><a title="The YUI ImageLoader Utility - Functional Examples" href="../../examples/imageloader/index.html">ImageLoader</a></li><li class="item"><a title="The YUI JSON Utility - Functional Examples" href="../../examples/json/index.html">JSON</a></li><li class="item"><a title="The YUI Layout Manager - Functional Examples" href="../../examples/layout/index.html">Layout Manager</a></li><li class="item"><a title="The YUI Logger Control - Functional Examples" href="../../examples/logger/index.html">Logger</a></li><li class="item"><a title="The YUI Menu Control - Functional Examples" href="../../examples/menu/index.html">Menu</a></li><li class="item"><a title="The YUI Paginator - Functional Examples" href="../../examples/paginator/index.html">Paginator</a></li><li class="item"><a title="The YUI Profiler Utility - Functional Examples" href="../../examples/profiler/index.html">Profiler</a></li><li class="item"><a title="The YUI ProfileViewer Control - Functional Examples" href="../../examples/profilerviewer/index.html">ProfilerViewer</a></li><li class="item"><a title="The YUI ProgressBar Control - Functional Examples" href="../../examples/progressbar/index.html">ProgressBar</a></li><li class="item"><a title="The YUI Resize Utility - Functional Examples" href="../../examples/resize/index.html">Resize</a></li><li class="item"><a title="The YUI Rich Text Editor - Functional Examples" href="../../examples/editor/index.html">Rich Text Editor</a></li><li class="item"><a title="The YUI Selector Utility - Functional Examples" href="../../examples/selector/index.html">Selector</a></li><li class="item"><a title="The YUI Slider Control - Functional Examples" href="../../examples/slider/index.html">Slider</a></li><li class="item"><a title="The YUI Storage Utility - Functional Examples" href="../../examples/storage/index.html">Storage</a></li><li class="item"><a title="The YUI SWF Utility - Functional Examples" href="../../examples/swf/index.html">SWF</a></li><li class="item"><a title="The YUI SWFStore Utility - Functional Examples" href="../../examples/swfstore/index.html">SWFStore</a></li><li class="item"><a title="The YUI Stylesheet Utility - Functional Examples" href="../../examples/stylesheet/index.html">Stylesheet</a></li><li class="item"><a title="The YUI TabView Control - Functional Examples" href="../../examples/tabview/index.html">TabView</a></li><li class="item"><a title="The YUI TreeView Control - Functional Examples" href="../../examples/treeview/index.html">TreeView</a></li><li class="item"><a title="The YUI Uploader Utility - Functional Examples" href="../../examples/uploader/index.html">Uploader (experimental)</a></li><li class="item"><a title="The YUI YAHOO Global Object - Functional Examples" href="../../examples/yahoo/index.html">YAHOO Global Object</a></li><li class="item"><a title="The YUI Loader Utility - Functional Examples" href="../../examples/yuiloader/index.html">YUI Loader</a></li><li class="item"><a title="The YUI Test Utility - Functional Examples" href="../../examples/yuitest/index.html">YUI Test</a></li><li class="item"><a title="YUI Reset CSS - Functional Examples" href="../../examples/reset/index.html">Reset CSS</a></li><li class="item"><a title="YUI Base CSS - Functional Examples" href="../../examples/base/index.html">Base CSS</a></li><li class="item"><a title="YUI Fonts CSS - Functional Examples" href="../../examples/fonts/index.html">Fonts CSS</a></li><li class="item"><a title="YUI Grids CSS - Functional Examples" href="../../examples/grids/index.html">Grids CSS</a></li><li class="sect">YUI Articles on the YUI Website</li><li class="item"><a title="Answers to Frequently Asked Questions about the YUI Library" href="http://developer.yahoo.com/yui/articles/faq/">YUI FAQ (external)</a></li><li class="item"><a title="Yahoo!'s philosophy of Graded Browser Support" href="http://developer.yahoo.com/yui/articles/gbs/">Graded Browser Support (external)</a></li><li class="item"><a title="Reporting Bugs and Making Feature Requests for YUI Components" href="http://developer.yahoo.com/yui/articles/reportingbugs/">Bug Reports/Feature Requests (external)</a></li><li class="item"><a title="Serve YUI source files from Yahoo! -- free, fast, and simple" href="http://developer.yahoo.com/yui/articles/hosting/">Serving YUI Files from Yahoo! (external)</a></li><li class="item"><a title="Best practices for working with web services while protecting user privacy" href="http://developer.yahoo.com/security/">Security Best Practices (external)</a></li></ul>
</div>
</div>
	</div><!--closes bd-->

	<div id="ft">
        <p class="first">Copyright &copy; 2010 Yahoo! Inc. All rights reserved.</p>
        <p><a href="http://privacy.yahoo.com/privacy/us/devel/index.html">Privacy Policy</a> - 
            <a href="http://docs.yahoo.com/info/terms/">Terms of Service</a> - 
            <a href="http://docs.yahoo.com/info/copyright/copyright.html">Copyright Policy</a> - 
            <a href="http://careers.yahoo.com/">Job Openings</a></p>
	</div>
</div>
<script src="../../assets/syntax.js"></script>
<script src="../../assets/dpSyntaxHighlighter.js"></script>
<script language="javascript"> 
dp.SyntaxHighlighter.HighlightAll('code'); 
</script>

<script src='../../assets/YUIexamples.js'></script>


</body>
</html>
